The term electrical connector shell is used to mean a box which is fixed to the rear portion of the connector proper, said connector preferably being an electrical connector. The function of the shell is firstly to provide a mechanical link between the cable, in particular an electric cable, and the electrical connector, and secondly to surround and protect the electric cable and its electrical conductors in the region where the electrical (or possibly optical) conductors are connected to the terminals of the connector.
It is often also necessary for the shell to provide continuity of cable shielding when the cable is an electric cable in order to be prevent the electrical signals conveyed by the cable from generating disturbances in the environment and, vice versa, in order to protect the cable and its electrical connector from external electromagnetic disturbances.
In some cases, the shell of the electrical connector must be relatively complex in shape, particularly for the purpose of receiving captive screws for fixing the electrical connector to the appliance to which it is to be connected. This applies, for example, with the electrical connectors used with microcomputers.
Because of the relatively complex shape of the shell, it is advantageous to be able to make the shell out of a material that lends itself easily to molding while still having sufficient electrical conductivity to provide a satisfactory shielding effect.
Such materials include, in particular, Zamak which is an alloy based on zinc, aluminum, copper, and magnesium. The drawback of such castable metal alloys that are good conductors of electricity is that in general their capacity for reversible elastic deformation is very small. Thus, with ordinary methods, it is more or less impossible to make a shell out of two parts that can be mechanically connected together by snap-fastening means. However, the snap-fastening technique is well known for shells or connector elements made out of moldable plastics materials.